390 Electrical Power Systems Technology
- Under excitation—operates at a lagging power factor (inductive ef-
fect). - Over excitation—operates at a leading power factor (capacitive ef-
fect).
Figure 14-29. Power re-
lationships of a three-
phase synchronous
motor: (A) Rotor cur-
rent versus stator cur-
rent—”V curves,” (B)
Rotor current versus
power factor